WHD.SG Firmware Update — July 2026

Firmware release: July 2026

THIS UPDATE IS FOR THE SOUNDSTREAM WHD.SG ONLY, FITTED TO 1998–2013 HARLEY-DAVIDSON STREET GLIDE & ULTRA MOTORCYCLES.

Attempting this update on any other model of head unit will corrupt the CPU, "bricking" it. Head units damaged by an incorrect firmware update are not covered by warranty.

Check the About screen at step 7 before you start — the version numbers name the model. If yours read WHDSG, you're on the right page. If they read WHDRG, use the WHD.RG update instead. This page is not for the newer SG.V2.

What this update fixes

  • Updates the CarPlay & Android Auto protocols
  • Adds custom handlebar programming
  • Corrects SiriusXM equalisation

Before you start

Read every step before you begin, and don't skip any. When this update goes wrong, it's usually down to what's on the flash drive — so take your time over steps 1 and 2.

You need a blank USB Type-A flash drive that meets all of the following:

Capacity 4GB minimum, 32GB maximum — 64GB and larger will not work
Format FAT32
Specification USB 2.0 or 3.0
Brand A reputable name brand — SanDisk, Samsung, etc. We use and recommend the SanDisk Cruzer

A flash drive of unknown USB specification will slow data transfer and can corrupt the system processors. If the drive isn't empty, format it first — here are instructions for formatting a flash drive in Windows.

The download is 96MB, so do that part on Wi-Fi before you head out to the bike. The update itself runs for a few minutes on the head unit, and it must not be interrupted — make sure your battery is healthy or the bike is on a tender.

Update instructions

Download WHDSG_202607.zip
96 MB — download on Wi-Fi

  1. Download WHDSG_202607.zip using the button above.

  2. Extract the zip. Copy ISPBOOOT.BIN and the update folder — with st25mcu.bin inside it — to the blank USB Type-A flash drive.

    This particular download has a stray file in it — delete it. Inside the update folder, alongside st25mcu.bin, you may see a second file called ._st25mcu_1.bin. It is left-over packaging junk, not part of the firmware. Delete it from the flash drive before you continue, or the WHD.SG is likely to report "This data is not compatible". Mac users won't see it (it's hidden); Windows users will.

    Don't rename anything else. The folder and the MCU file extract in lower case — update and st25mcu.bin — while the screenshot below, taken on an earlier build, shows the folder in capitals. Either is fine: the flash drive and the head unit both ignore capitalisation. What matters is that the spelling is unchanged and nothing extra has been added to the names.

    Once the stray file is gone, the two remaining items must sit in the root of the drive, with nothing else on it:

    ISPBOOOT.BIN file and update folder copied to the root of a blank USB flash drive

    On a Mac: extracting the zip also creates a hidden __MACOSX folder. Delete it from the flash drive too.

  3. Connect the flash drive to the USB Type-A input for the WHD.SG. On these bikes it is often fitted in place of the cigarette lighter.

  4. Turn the bike on to accessory power.

  5. After the WHD.SG completes its start-up sequence the main menu should appear. If not, select the Home icon in the top left corner, or the Back arrow in the top right corner, until the main menu is displayed. Select the Settings gear icon on the shortcut bar.

    SoundStream WHD.SG main menu with the Settings gear icon on the shortcut bar
  6. Tap System Settings at the top of the settings list.

    SoundStream WHD.SG settings list with System Settings at the top
  7. Tap About at the bottom of the System Settings list. This displays the current MCU and SOC software versions and the hardware version of your WHD.SG.

    SoundStream WHD.SG System Settings list scrolled to About
  8. Select the Update button, centre, below the Hardware version.

    SoundStream WHD.SG About screen with the Update button
    Getting "This data is not compatible"? First check you deleted ._st25mcu_1.bin from the update folder — on this model that's the most likely cause. Otherwise, double-check the file names: there must be a file named ISPBOOOT.BIN — note the three O's — and a folder named update with a file inside it named st25mcu.bin. Capitalisation doesn't matter, but any extra characters do. Also delete any other hidden files, including the __MACOSX folder. Then repeat steps 4–8.
  9. A New Firmware Version pop-up appears. Check that it reads:

    • MCU WHD14+-250410-WHDSG
    • SOC WHDSG-260701-01

    If both are correct, tap Update.

    SoundStream WHD.SG New Firmware Version pop-up showing the MCU and SOC versions

    The MCU line starting with WHD14+ is correct and expected here — the WHD.SG shares its MCU firmware family with the WHD14+. After the update the About screen shortens it to WHDSG-250410. Nothing has gone wrong.

  10. After a moment the MCU Update pop-up appears with a progress bar. When it completes, the screen may switch off or flash for a few moments. This is normal — don't touch anything.

    MCU Update progress bar on the SoundStream WHD.SG screen
  11. After several seconds the SOC Update pop-up appears with its own progress bar. When it finishes, the WHD.SG restarts. Once it has restarted you can remove the flash drive from the USB input.

    SOC Update progress bar on the SoundStream WHD.SG screen
  12. To confirm the update was successful, repeat steps 5–7. You should now see:

    • MCU: WHDSG-250410
    • SOC: WHDSG-260701-01
    SoundStream WHD.SG About screen after a successful update

If the versions don't match

Double-check that the file names are correct — ISPBOOOT.BIN, and a folder named update with a file inside named st25mcu.bin, with no stray ._st25mcu_1.bin. Correct the drive contents and repeat steps 3–12.

Still stuck? Talk to us.

We'd rather walk you through it than have you guess.
Email: support@motorcycleaudio.com.au
Phone: (07) 3350 1354
Motorcycle Audio Australia — authorised SoundStream dealer for Australia & New Zealand